THE BREATH OF LIFE 



Does not a man imply a cooler planet and a greater 

 depth and refinement of soil than a dinosaur? Only 

 after a certain housecleaning and purification of the 

 elements do higher forms appear; the vast accu- 

 mulation of Silurian limestone must have hastened 

 the age of fishes. The age of reptiles waited for the 

 clearing of the air of the burden of carbon dioxide. 

 The age of mammals awaited the deepening and the 

 enrichment of the soil and the stability of the earth's 

 crust. Who knows upon what physical conditions 

 of the earth's elements the brain of man was de- 

 pendent? Its highest development has certainly 

 taken place in a temperate climate. There can be 

 little doubt that beyond a certain point the run- 

 ning-down of the earth-temperature will result in a 

 running-down of life till it finally goes out. Life is 

 confined to a very narrow range of temperature. 

 If we were to translate degrees into miles and repre- 

 sent the temperature of the hottest stars, which is 

 put at 30,000 degrees, by a line 30,000 miles long, 

 then the part of the line marking the limits of life 

 would be approximately three hundred miles. 



Life does not appear in a hard, immobile, utterly 

 inert world, but in a world thrilling with energy and 

 activity, a world of ceaseless transformations of 

 energy, of radio-activity, of electro-magnetic cur- 

 rents, of perpetual motion in its ultimate particles, a 

 world whose heavens are at times hung with rain- 

 bows, curtained with tremulous shifting auroras, 

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